Oxadiazolone compounds



United States Patent 12 Claims. ((31. 260307) ABSTRACT OF THE DISCLOSURE The invention provides new 3-phenylcarbamoy1-1,3,4- oxadiazol-Z-ones, optionally substituted in the 5-position, which are useful in agriculture against foliar parasites.

This invention relates to new oxadiazolone compounds, a process for their preparation and compositions containing them.

The new oxadiazolone compounds of the present invention are those of the general formula:

R i 0 R1 wherein R represents a hydrogen atom or an alkyl group, a phenyl group which may carry a halogen atom or an alkyl, alkoxy or hydroxyl substituent, an aralkyl group containing 7 to 12 carbon atoms (preferably benzyl), a cycloalkyl group containing 3 to 6 carbon atoms, a fiveor six-rnembered heterocyclyl group with one or more hetero atoms selected from oxygen, sulphur and nitrogen, or a cyano, alkoxy, alkylthio, alkoxyalkyl, alkylthioalkyl, alkoxycarbonyl, alkylcarbamoyl, alkanesulphonyl or alkanesulphonylalkyl group, and

represents phenyl or phenyl carrying at least one substituent selected from halogen atoms, and alkyl, alkenyl, alkoxy, alkenyloxy, alkylthio, alkenylthio, trifiuoromethyl, cyano and dialkylamino groups. It is to be understood that in this specification and accompanying claims the alkyl, alkoxy, alkane and alkenyl groups referred to contain at most six carbon atoms.

According to a feature of the invention, the oxadiazolone compounds of Formula I are prepared by the process which comprises reacting an isocyanate of the formula:

is as hereinbefore defined) with a 1,3,4-oxadiazol-2one of the formula:

II (wherein a temperature between ambient temperature, i.e. 10-30 C., and the reflux temperature of the reaction mixture. It is advantageous to employ a tertiary organic base, for example triethylarnine, as condensing agent.

The 1,3,4-oxadiazol-2-one starting materials of Formula III can be obtained by the action of phosgene on a hydrazide of the formula RCONHNH wherein R is as hereinbefore defined. The reaction is preferably carried out in water.

The oxadiazolone compounds of Formula I possess remarkable fungicidal properties which are especially useful in agriculture; in particular, they are particularly active against foliar parasites such as apple-scab, potato blight and tobacco mildew. Preferred compounds are those in which R represents a hydrogen atom or an alkyl, phenyl, cycloalkyl, alkoxyalkyl, alkylthioalkyl, alkoxycarbonyl, alkylcarbamoyl or alkanesulphonylalkyl group, and the grouping represents phenyl or phenyl carrying at least one substituent selected from halogen atoms and alkyl, alkoxy, alkenyloxy, trifiuoromethyl and dialkylamino groups. Of outstanding utility as fungicides are those compounds of Formula I in which R represents an alkyl group of 2 to 4 carbon atoms and R is in the 4-position of the henzene ring and represents a methoxy or dimethylamino group; in particular, 3-(4-methoxyphenyl)carbamoyl-5- butyl-1,3,4-oxadiazol-2-one, 3-(4-methoxyphenyl) carbamoyl-5-tert.-butyl 1,3,4 oxadiazol-Z-one, 3-(4-dimethy1- aminophenyl)carbamoyl-5-tert.-butyl 1,3,4-oxadiazol-2- one, 3-(4 dimethylaminophenyl)carbarnoyl-S-isopropyl- 1,3,4-oxadiazo1-2-one, 3 (4-methoxyphenyl)carbamoyl- S-ethyl 1,3,4 oxadiazol 2 one, 3-(4-methoxyphenyl) carbamoyl-S-propyl 1,3,4 oxadiazol 2 one, 3-(4-me thoxyphenyl)carbamoyl 5 isopropyl 1,3,4 oxadiazol- 2-one, 3-(4-dimethylaminophenyl)carbamoyl-5-ethyl-l,3, 4-oxadiazol-2-one, 3-(4-dimethylaminophenyl)carbamoyl- 5-propyl-1,3,4-oxadiazol-2-one, and 3-(4-dimethylaminophenyl)carbamoyl 5 butyl-1,3,4-oxadiazol-2-one, especially the four first-mentioned compounds.

According to a further feature of the present invention the are provided fungicidal compositions containing at least one oxadiazolone compound of Formula I in association with one or more diluents compatible with the oxadiazolone and suitable for use in agricultural fungicidal compositions. Preferably the compositions contain between 0.005 and by weight of oxadiazolone. The compositions may be solid if there is employed a powdered solid compatible diluent such as talc, calcined magnesia, kieselguhr, tricalcium phosphate, powdered cork, absorbent charcoal, or a clay such as kaolin or bentonite. Instead of a solid diluent, there may be used a liquid in which the oxadiazolone is dissolved or dispersed. The compositions may thus take the form of suspensions, emulsions or solutions in organic or aqueousorganic media, for example aromatic hydrocarbons such as toluene or xylene or mineral, animal or vegetable oils, or mixtures of these diluents. The compositions in the form of suspensions, emulsions or solutions may contain wetting, dispersing or emulsifying agents of the ionic or non-ionic type, for example sulphoricinoleates', quaternary ammonium derivatives or products based on condensates of ethylene oxide, such as the condensates of ethylene oxide with octylphenol, or fatty acid esters of anhydrosorbitols which have been rendered soluble by etherification of the free hydroxy groups by condensation with ethylene oxide. It is preferable to use agents of the non-ionic type because they are not sensitive to electrolytes. When desired, emulsions of the oxadiazolones may be used in the form of self-emulsifying concentrates containing the active substance dissolved in the emulsifying 121 (1949), by the action of phosgene on butyryl-hydrazine.

Example II A mixture of S-methyl-l,3,4-oxadiazol-2-one (5 g.) and agent Q in Solvent cofltaining an emulsifying agent 5 4-dimethylaminophenylisocyanate (8.1 g.) in anhydrous ll Wlth the Oxadlazolone and a Slmple benzene (50 cc.) is heated under reflux for 2 hours in the afifhtlon of Water to Such Concfimrates Producmg compo presence of triethylamine (3 drops). The solution is cooled SI'EIOIIS fl y for to 20 C., and the precipitate formed filtered off, washed Th solid wmp a p e b prepared with benzene and dried. There is thus obtained 3-(4-di grlndlng the oxad'lalolone wlth Sohd F by l methylaminophenyl)carbamoyl-S-methyl-1,3,4-0xadiazolpregnatlng the solid diluent with a solution of the oxadi- Zone (125 which, after recrystallisation f 1 2-di. azolone in a volatile solvent, evaporating the solvent, chloroethanemelts at 2 2 Q and if necessary grinding the product so as to obtain a The 5 methy1 13,4 oXadiaZo1 2 one p 4 Q) P and y optlonally Incorporate a Weftmg employed as starting material is prepared according to A. dispersing agent, for example of the types hereinbefore 15 Dornow and K Bruncken, 1 i described. E 1 III The oxadiazolone compounds of Formula I are prefer- Xamp e ably employed for fungicidal purposes in a quantity of To a solution of 5-tert.-butyl-1,3,4-oxadiazol-2-one 100 to 200 g. of active substance per hectolitre of water. (14.2 g.) in anhydrous benzene (80 cc.) there is added,

The following three examples illustrate the preparation over a period of 5 minutes and in the presence of triethylof oxadiazolone compounds of the invention. amine (3 drops), a solution of 4-methoxyphenylisocya- Example I nate (14.9 g.) in anhydrous benzene (20 cc.). The reaction mixture is stirred for 4 hours at ambient temperature a Solutlon 0f -P PY and then the solvent is removed by distillation in vacuo. g m anhydrous benzene there a added There is obtained 3-(4-methoxyphenyl)carbamoyl-S-terL- ethvlamme 3 p and then, Over a Penod 5 butyl-1,3,4-oxadiazol-2-one g.) which, after recrystallltes, a sohlllon of Phfinyhsocyanate 111 lisation from a mixture of cyclohexane and benzene, melts drous benzene (20 cc.). The temperature rises to 32 C. at 118 C The reaction mixture is heated under reflux for 2 hours Th 5 t t,-b ty1-1,3,4-o adi 1-2- ne (B,P, 103-104 and then cooled to 20 C. The benzene is distilled 011 in 30 3 005 mm Hg) gmploygd as Starting material is Vacllo T0 Yield -P Y -P PY pared by the action of phosgene on trimethylacetylhydrazol-2-one (24 g.) which, after recrystallisation from cycloin hexane, melts at 97 C. I By proceeding as described in Examples I to III and The 5-pr0py1-1,3, -0Xad a 1- -0n C-/ employing appropriate starting materials of Formulae II 0.1 mm Hg) employed as starting material is prepared 35 and III, there are also obtained the products identified in according to A. Nornow and K. Bruncken, Berichte, 82, the following table:

TABLE NNC 0-NHQ Bl L0 B1 Position Melting "R -R1 Of R1 point,

H 00H.-. 4 158-159 OH -H -CH3 0 CH; 4 163 G H5 -H 4321515 -OCH; 4 111 C2H5 -N(CHa)z 4 138 -oiH1 OCH; 4 97 C3H1 -N(CH3)2 4 125 CH(CH3)g -H 74-75 cH(oHi)i -0CHi 4 113-114 -CI-I(CH3)5 N(0Hi)i 4 95-96 C4Hg 'H 73 C4H9 CH3 4 66 C4Hn 0CH3 4 84 C4Ho -N(CH3)2 4 129 -oiHn 1 4 127. 5-128 -C4Ho -CF3 3 92 o(oH3)n H 102 -C(OH3)3 -0 CH 0 CH3 3 and 4 140 C(OHa)a -O CHz-CH=CH2 4 93 0 (CH3): a)2 4 127. 5-128 --C(CH3)3 O1 4 128 O(CHi)e CFi 3 120 '-C5II11 H 82 -05H11 "OCH! 4 80 E H 130 CH2OCH; -H 10a -oHiocH3 0CH 4 11s OOOC2H5 H -151 c0oo,H6 OCH3 4 15s -C5H5 0 CH3 4 158 CONHCH3 OCHa 4 oH(oHn)soH3 -OCH;; 4 120 -CH2SGH3 H 115 -CH2SOH3 0 cm 4 119. 5-120 -CH(CH3)SOH;: -H

The following examples illustrate fungicidal compositions according to the present invention.

Example IV To 3 (4 methoxyphenyl)carbamoyl 5 butyl- 1,3,4-oxadiazol-2-one (100 g.) there is added talc (95 g.) and a condensation product of ethylene oxide with p-octylphenol (5 g.). After grinding, the powder obtained can be used, after dilution with water to give 200 g. of powder per 100 litres of water, for protecting plants against attack by fungi.

Example V To 3 (4 methoxyphenyDearbamoyl 5 butyl- 1,3,4-oxadiazol-2-one (500 g.) there are added calcium lignosulphite' (25 g.) and kaolin (475 g.). After grinding and screening, the powder obtained can be used, after dilution with water to give 400 g. of powder per 100 litres of water, to protect plants against attack by fungi.

Acconding to another feature of the invention, a method for the treatment of plants or trees infected by fungi, or to prevent infection by fungi, comprises applying to the plants or trees a fungicidal composition containing at least one oxadiazolone compound of general Formula I. Apple trees, potato plants or tobacco plants may, for example, be treated to control, or prevent infection by, apple-scab, or potato blight or tobacco mildew, respectively.

We claim:

1. Oxadiazolone compounds of the formula:

alkylthioalkyl, alkoxycarbonyl, alkylcarbamoyl or alkanesulphonylalkyl, and the grouping represents phenyl or phenyl carrying at least one substituent selected from halogen, alkyl, alkoxy, alkenyloxy, trifluoromethyl and dialkylamino, the said alkyl, alkoxy, alkane and alkenyl groups containing at most six carbon atoms.

2. Oxadiazolone compounds according to claim 1 wherein R represents alkyl of 2 through 4 carbon atoms and R is in the 4-position of the benzene ring and represents rnethoxy or dimethylamino.

3. 3 (4 methoxyphenyDcarbamoyl 5 butyl-1,3,4- oxadiazol-Z-one.

4. 3 (4 methoxyphenyDcarbamoyl 5 tert. butyl- 1,3,4-oxadiazol-2-one.

5. 3 (4 dimethylaminophenyl)carb-amoyl 5 tertbutyl-l,3,4-oxadiazol-2-one.

6. .3 (4 dimethylaminophenyl)carbamoyl 5 isopropyl-l,3,4-oxadiazol-2-one.

7. 3 (4 methoxyphenyDcarbamoyl 5 ethyl 1,3,4- oxadiazol-Z-one.

8. 3 (4 methoxyphenyDcarbamoyl 5 propyl- 1,3,4-oXadiazol-2-one.

9. 3 (4 methoxyphenyl)carbamoyl 5 isopropyl- 1,3,4-oxadiazol-2-one.

10. 3-(4 dimethylaminophenyl)carbamoyl 5 ethyl- 1,3,4-oxadiazol-2-one.

11. 3 (4 dimethylaminophenyl)carbamoyl 5 propyl-l,3,4-oxadiazol-2-one.

12. 3-(4 dimethylaminophenyl)carbamoyl 5 butyl- 1,3,4-oxadiaZol-2-one.

References Cited UNITED STATES PATENTS ALTON D. ROLLINS, Primary Examiner. 

